Sudden Death Syndrome

  • Symptoms

  • Trigger

  • Biological Control

  • Chemical Control

  • Preventive Measures

Sudden Death Syndrome

Fusarium virguliforme

Fungus


In a Nutshell

  • Scattered, diffuse, yellow spots appear between leaf veins.
  • Spots grow into necrotic areas that may fall out the leaf.
  • Signs of rot in internal tissue of stem and root indicated by brown discoloration.
  • Flowers may abort and pods may not develop or fill.

Hosts

Soybean

Symptoms

Small, pale green circular spots appear on leaves during flowering stage. Interveinal chlorosis and later necrosis show on leaves. As the disease progresses, the necrotic tissue between the veins may die and fall out, giving the leaves a ragged appearance. Leaves can eventually dry, curl or drop off but the petiole remains attached to the stem. Signs of rotting (brown discoloration) appear in the internal tissues of the lower stem and main root. Flowers may abort and pods may not develop or fill.

Trigger

The fungus Fusarium virguliforme survives as spores in soil or on infested crop residues. It infects and colonizes plants through the root early in the vegetative stage but symptoms may become apparent only during flowering. The infection is favored by cool and wet soils, rainy weather conditions, densely planted fields, poor drainage or compacted soils. Wounds of soybean cyst nematodes, pests and mechanical injuries from poor handling practices also favor the infection risk.

Biological Control

To this day no biological control of the fungus is known

Chemical Control

Always consider an integrated approach with preventive measures together with biological treatments if available. Foliar fungicides are not effective because the fungus remains in the root system. Instead, apply specific fungicides, such as fluopyram to the seeds.

Preventive Measures

Use high quality certified seeds.,Plant resilient tolerant or resistant varieties.,Plant early in the season to avoid adverse weather conditions.,Leave sufficient space between plants to ensure good ventilation.,Rotate with non-host crops for the given period.,Monitor your field for first symptoms.,Provide good drainage.,Plow the field to avoid soil compaction.